1. Field of the invention
This invention relates to a lifting device for use in underground mining operations, and more particularly, to a lifting device which is adapted to be connected to a tractor scoop having a movable pusher member positioned therein and pivoted in an upward path upon movement of the pusher member to bring a roof support member positioned on the lifting device into abutting contact with a mine roof.
2. Description of the Prior Art
In the field of underground mining it is well known to support a mine roof formed as material is removed from the mine face by means of roof support members or crossbeams. The roof support members are usually raised into abutting contact with the mine roof and maintained in position by suitable blocking. After the roof support members are raised into abutting contact with the mine roof and blocked in position, the roof support members are anchored to the mine roof by conventional roof bolts.
The hand setting of roof support members by mine personnel presents a hazardous condition since hand setting requires these individuals to work under unsupported roof, and the danger of mine roof collapse is an ever present one.
In order to protect mine personnel from hazards associated with hand setting roof support members, U.S. Pat. No. 2,772,871 discloses an apparatus lifting roof support members into abutting contact with a mine roof which is connected with a continuous mining machine. The roof support member lifting apparatus includes a pair of elevating beams positioned longitudinally along the top of the continuous mining machine on each side of the mining machine longitudinal conveyor. Each elevating beam has an end portion pivotally connected to the rear end of the mining machine, and the opposite ends of the elevating beams extend towards the front end of the machine. A roof support member is positioned on saddles connected with the opposite ends of the pair of elevating beams so that the roof support member lies transverse to the longitudinal axis of the machine. Hydraulic cylinders connected between the mining machine and each elevating beam are operable to raise the elevating beams to bring the roof support member into abutting contact with the mine roof.
While it has been suggested by the prior art to mount a roof support member lifting apparatus to a continuous mining machine and hydraulically lift a roof support member positioned on the lifting apparatus into abutting contact with a mine roof, there is a need for a lifting device capable of raising a roof support member into abutting contact with a mine roof that is adapted to be easily connected to a conventional mine scoop tractor. The lifting device must be capable of supporting a roof support member and raising the roof support member into abutting contact with the mine roof upon horizontal movement of a pusher member positioned within the tractor scoop. The lifting device must be operable to raise a roof support member into abutting contact with the mine roof above and forward of the scoop tractor to eliminate the safety hazards present when these roof support members are manually raised into position by mine personnel.